Figure WN21.2 - The P element is found in Drosophila species of the D. willistoni and D. saltans groups, and in all present-day populations of D. melanogaster.

Figure WN21.2. The P element is found in Drosophila species of the D. willistoni and D. saltans groups, and in all present-day populations of D. melanogaster. However, it has not been found in D. melanogaster’s sister species (D. simulans, D. sechellia, and D. mauritiana), or in old laboratory stocks of D. melanogaster (“M strains”). The D. melanogaster sequence is almost identical to that of D. willistoni, suggesting recent horizontal transfer. In species with “weak hybridization,” evidence for presence of P elements is ambiguous. (From Fig. 2 in Engels 1996.)